Objectives Reactive hyperaemia following thigh compression increases arterial inflow and venous outflow. The net effect can be measured by changes in calf volume quantified using air-plethysmography. The objective was to investigate the effect of thigh compression on venous return. Method The right legs of 19 consecutive volunteers (14 male), median age 31 (25–56) years, were studied in the supine position using air-plethysmography. The clinical, etiological, anatomical, pathophysiological (CEAP) class was C0. A thigh-cuff, 12 cm wide, was inflated in increments of 10 mmHg, from 0 to 80 mmHg. After each inflation step, the calf volume increased to a plateau and was recorded. At 80 mmHg, the thigh-cuff was deflated suddenly with the calf volume decreasing until baseline. Calf volume changes were recorded and stored for analysis. Results There was a stepwise increase in the venous volume of the calf with each incremental rise in thigh-cuff pressure up to 80 mmHg (p < .0005, Friedman). The median (interquartile range) increase in venous volume from 0 to 80 mmHg was 87 (65–113) mL (p < .0005, Wilcoxon). The volume change below the original baseline following thigh-cuff release was −16 (−12 to −25) mL (p < .0005, Wilcoxon). Conclusions Once optimised, intermittent pneumatic compression of the thigh may have a therapeutic role in augmenting the venous return and reducing leg swelling in patients.
Answers to the invited commentaries on 'Venous return simplified with air-plethysmography, modelling and Sack Theory' by CR Lattimer, A Obermayer
